A hairline that has crept back a little. A crown that shows under bright bathroom lights. For many men, hair loss starts quietly in their twenties or thirties. Most of the time it follows a familiar pattern, but sometimes other factors add to it. This guide explains the role of DHT, what blood tests can and cannot show, and what the Male Hair Loss Profile in the BPR catalogue includes.
Male pattern hair loss and DHT
Male pattern hair loss, also called androgenetic alopecia, is extremely common. A 2020 review notes that it affects up to 80% of men by the age of 80, with progressive thinning in a defined pattern (York et al., 2020). Genes and androgens play the key roles: in susceptible hair follicles, the follicles gradually shrink, producing finer and shorter hairs.
The androgen most closely involved is dihydrotestosterone (DHT). LML describes DHT as a hormone derived from testosterone. A 2018 review notes that male pattern hair loss is mediated by DHT and affects over 50% of men over 50 (Said and Mehta, 2018). The enzyme that converts testosterone into DHT, 5-alpha reductase, is the target of finasteride, one of the main treatments.
Does a DHT blood test show pattern hair loss?
Not on its own. Pattern hair loss depends largely on how sensitive the follicles are, so men with typical DHT levels can still lose hair. The Dihydrotestosterone test is in the catalogue for situations where a doctor wants that value, for example alongside other hormones. LML notes that DHT results take about two weeks after the sample reaches the laboratory.
When other factors may be involved
The NHS notes that male pattern baldness usually runs in families and that a GP can often tell the type of hair loss by looking at it. It also lists illness, stress, weight loss and iron deficiency as causes of temporary hair loss (NHS, Hair loss). Diffuse shedding, sudden loss, or thinning together with tiredness or other symptoms is where blood tests can be more informative.
What the Male Hair Loss Profile includes
LML designed the Male Hair Loss Profile to look at the internal factors that may contribute to hair loss. It includes:
- Hormones: testosterone, free testosterone (calculated), SHBG, free androgen index, FSH, LH, prolactin, DHEA sulphate, cortisol and oestradiol.
- Thyroid: TSH and free T4. LML notes that thyroid disorders are a common but overlooked cause of thinning hair in men.
- Nutrients: vitamin D, vitamin B12, folate, zinc and ferritin.
- Liver and kidney markers, and a full blood count to look for anaemia or signs of inflammation.
DHT itself is not part of this profile; it is a separate test if your doctor wants it.
Testing before or during treatment
The NHS describes finasteride and minoxidil as the main treatments for male pattern baldness, noting that they do not work for everyone and only work while they are used (NHS, Hair loss). A 2023 review in Drugs covers these and newer options in detail (Devjani et al., 2023).
LML suggests the profile for men who are using or considering treatments such as finasteride or minoxidil and want to understand whether hormones or nutrition may be playing a part. Because finasteride acts on the testosterone and DHT pathway, and because a 2018 review reports that some men experience sexual side effects (Said and Mehta, 2018), some men like to have a hormone baseline before starting. Treatment decisions should always be made with a doctor.
